Hemi Qu

Nanning Normal University · School of chemistry and materials

Carbon nanotube (CNT)-based chemiresistors are promising gas detectors for gas chromatography (GC) due to their intrinsic nanoscale porosity and excellent electrical conductivity. However, fabrication reproducibility, long desorption time, limited sensitivity, and low dynamic range limit their usage in real applications. This paper reports a novel...

Gas separation and detection technology is closely related to people’s daily production and life. With the emergence of various detection equipment, it has made remarkable progress in recent decades. Gas sensing materials play an important role in the process of gas separation and detection. Compared with traditional gas sensing materials, metal-or...

The presence of chemical warfare agents (CWAs) in the environment is a serious threat to human safety, but there are many problems with the currently available detection methods for CWAs. For example, gas chromatography–mass spectrometry cannot be used for in-field detection owing to the rather large size of the equipment required, while commercial...

A microfluidic film bulk acoustic wave resonator gas sensor (mFBAR) adapted specifically as an in-line detector in gas chromatography was described. This miniaturized vapor sensor was a non-destructive detector with very low dead volume (0.02 μL). It was prepared by enclosing the resonator in a microfluidic channel on a chip with dimensions of only...

Gravimetric resonators based on Micro/Nanoelectromechanical System (M/NEMS) are potential candidates in developing smaller, less expensive, and higher performance gas sensors. Metal organic frameworks (MOFs), with high surface areas, recently come into focus as advanced nano-porous sensitive materials in micro gravimetric gas sensors. The surface o...

Flexible ammonia (NH3) sensors based on one-dimensional nanostructures have attracted great attention due to their high flexibility and low-power consumption. However, it is still challenging to reliably and cost-effectively fabricate ordered nanostructure-based flexible sensors. Herein, a smartphone-enabled fully integrated system based on a flexi...

Micro gas chromatography (μGC) has been continuously gaining attention since the last century owing to multiple favorable characteristics, such as its small size, low power consumption and minimal production and maintenance costs. μGC has the potential to provide practical solutions to emerging analytical challenges in security, health, and environ...

Hierarchical assemblies of nanomaterial superstructures with controlled orientation affords a multitude of novel properties of plasmonics and broad applications. Yet constructing multi-functional superstructures with nanoparticles positioned in desired locations remains challenging. Herein, gold nanorods (GNRs) assembled in stripe patterns with con...

One-dimensional organic nanostructures are essential building blocks for high performance gas sensors. Constucting as e-nose type sensor array is the current golden standard in develping portable system for gas mixtures detection. However, facile fabrication of nanoscale sensor array is still challenging due to the high cost of the conventional nan...

This paper reports a novel miniaturized detector for gas chromatography based on film bulk acoustic resonator (FBAR) sensor array. Polymer coated FBAR demonstrated detection limit of parts per million (ppm) concentrations for several volatile organic vapors. Orthogonal selectivity between n-pentane and acetone is achieved by integrating different p...

This paper reported a high-performance e-nose type chemiresistive gas sensor composed of graphene oxide (GO) doped poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanowires. Large scale and well-defined sub-100 nm nanowires were prepared using nanoscale soft lithography in a highly efficient and facile way, facilitating subseque...

In this paper, we develop a novel dual-mode gas sensor system which comprises a silicon nanoribbon field effect transistor (Si-NR FET) and a film bulk acoustic resonator (FBAR). We investigate their sensing characteristics using polar and nonpolar organic compounds, and demonstrate that polarity has a significant effect on the response of the Si-NR...

This work reported a wireless controlled micro-actuator system for rapid heating and mixing of multiple droplets using integrated arrays of micro-fabricated 2.5 GHz solid-mounted thin-film piezoelectric resonators (SMRs) and a millimeter-scale omnidirectional antenna. An equivalent circuit is proposed to analyze the mechanism of the heating, mixing...

Resistive devices composed of one dimensional nanostructures are promising candidate for next generation gas sensors. However, the large-scale fabrication of nanowires is still a challenge, restricting the commercialization of such type of devices. Here, we reported a highly efficient and facile approach to fabricate poly(3,4-ethylenedioxythiophene...

On-chip integrating several functional components for developing integrated lab-on-a-chip microsystem remains as a challenge. In this work, by employing multiple microelectromechanical resonators both as actuators and sensors, on-chip heating, mixing and chemical reaction monitoring are successfully demonstrated. Mechanism studies using COMSOL simu...

This paper describes the detection of volatile organic compounds (VOCs) using an e-nose system based on a virtual sensor array (VSA). The VSA was realized by seven different resonant modes of a single piezotransduced silicon bulk acoustic wave resonator (PSBAR) which can greatly reduce the complexity of a conventional e-nose system. The PSBAR was d...

acoustofluidics. This paper reports a minimized bio-particles manipulation tool utilizing localized ultrahigh frequency acoustic resonators (UHF-AR). The resonator works at frequency of 1540 MHz, which is high enough to break through scale effect and trigger localized acoustofluidic streaming (in formation of 3-D vortices) within microfluidic syste...

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In this work, a smartphone-enabled platform for easy and portably colorimetric analysis of 2,4,6-trinitrotoluene (TNT) using amine-trapped PDMS is designed and implemented. The amine-trapped PDMS is simply prepared by immersing the cured PDMS in aminosilane solutions forming an amine-containing polymer. After contacting with TNT-containing solution...

We developed a highly sensitive humidity sensor based on the combination of ultrahigh-frequency film bulk acoustic resonator (FBAR) and nano-assembled polyelectrolyte (PET) thin films. The water molecule absorption efficiency was optimized by forming loosely-packed PET nanostructures. Then, the humidity sensing characteristics were analyzed in term...

We present an acoustic microfluidic mixing approach via acousto-mechanically induced micro-vortices sustained by localized ultrahigh frequency (UHF) acoustic fields. A micro-fabricated solid-mounted thin-film piezoelectric resonator (SMR) with a frequency of 1.54 GHz has been integrated into microfluidic systems. Experimental and simulation results...

The thin film bulk acoustic resonator (FBAR) array based on MEMS can realize high throughput detection in sensing a variety of volatile gases. In this paper, by virtue of modifying the surface of film bulk acoustic resonators with different functional groups to form sensor array, the volatile gas can interact differently with different chemical fun...

In this paper, we have modeled and analyzed affinities and kinetics of volatile organic compounds (VOCs) adsorption (and desorption) on various surface chemical groups using multiple self-assembled monolayers (SAMs) functionalized film bulk acoustic resonator (FBAR) array. The high-frequency and micro-scale resonator provides improved sensitivity i...

This paper describes the detection of volatile organic compounds (VOCs) using an e-nose type integrated microfabricated sensor array, in which each resonator is coated with different supramolecular monolayers: p-tert-butyl calix[8]arene (Calix[8]arene), 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine (Porphyrin), beta-cyclodextrin (β-CD) and cucurbi...

A new surface functionalization scheme for nano-Bio field effect transistors (FETs) using biocompatible polyelectrolyte thin films (PET) is developed. PET assemblies on Si nanowires (Si-NWs) are driven by electrostatic interactions between the positively charged polymer backbone and negatively charged Si/SiO2 surface. Such assemblies can be directl...

In this work, a new method to tune the resonant frequency of micro-fabricated resonator using molecular layer-by-layer (LbL) self-assembly approach is demonstrated. By simply controlling the polymer concentration and the number of layers deposited, precisely tuning the frequency of micro-fabricated resonators is realized. Due to its selective depos...

Aromatic diimides have attracted much attention due to their unique properties and potential applications for n-channel organic field effect transistors (OFETs). In this study, N,N′-dialkyl-6,13-dicyano pentacene-2,3:9,10-bis(dicarboximide) (1) was synthesized and used in n-channel OFETs. The photophysical, electrochemical and thermal properties of...

6,13-Dibromopentacene [2,3:9,10]-bis(dicarboximide) (1) was synthesized for the first time by using in situ generated benzo[1,2-c:4,5-c']difuran as a key intermediate. Compound 1 exhibits good photostability in comparison to other pentacene derivatives and it can be further functionalized by Pd-catalyzed coupling reactions to give a series of solub...

Acenes, linearly fused aromatic hydrocarbons, have been the subjects of extensive research because of interesting electronic properties associated with their linear delocalized π-system. The potential applications of these acene-based materials in electronic devices such as field-effect transistor (FET), light-emitting diode (LED) and solar cell ha...

H-shaped bridged oligothiophenes HT-1 and HT-2 were synthesized by two different approaches. Different from normal oligothiophenes, HT-1 and HT-2 showed low band gaps and amphoteric redox behaviors due to intramolecular charge transfer, which is further supported by time-dependent DFT calculations.

Fused bispentacenequinone 2 was synthesized by photocyclization of bispentacenequinone 1. Unusual regioselective Michael addition was observed for 2 when excess aryl Grignard reagent was used. Subsequent acidification and oxidation in air gave diaryl-substituted bispentacenequinone 3. Tetra-aryl-substituted fused bispentacenequinone 4 was obtained...

A heptacene derivative 1 substituted with four electron-deficient trifluoromethylphenyl and two triisopropylsilylethynyl (TIPSE) groups was prepared by a new synthetic strategy. Photo-oxidative resistance studies showed that this newly developed heptacene compound persisted 47 h in solution under ambient light and air conditions, and it represents...

Synthesis of n-type organic semiconductors with high electron mobilities, good environmental stability, and good processability is an urgent task in current organic electronics. This is because most of π-conjugated materials are p-type and prefer to transport positive hole carriers. In this article, a series of new dicarboxylic imide-substituted po...

A new class of oligothiophene–anthracene co-oligomers, 9,10-bis(2-dodecyloligothienylvinyl)anthraceneTnA (n = 1, 2 and 3), were synthesized and characterized. The photophysical and electrochemical properties of these oligomers demonstrated an increased conjugation length with increasing number of thiophene units. These oligomers also exhibited rela...

A series of triphenylene and trinaphthylene carboximides were synthesized mainly through Diels-Alder reactions between the in situ generated radialenes and N-alkylmaleimides. High electron affinity was obtained due to the attachment of electron-withdrawing carboximide groups. These disklike molecules can assemble into one-dimensional columnar struc...